This application claims the priority of European application 961 15 639.5 filed in the European Patent Office on Sep. 30, 1996, the disclosure of which is expressly incorporated by reference herein.
The present invention relates to a slide bearing having a lubrication groove as well as to a gear pump having a slide bearing of this type.
It is known that slide bearings for gear pumps are often lubricated by the delivered medium because it may be assumed that, because of the eccentricity of the shaft in the slide bearing, which results in an increased gap width on the no-load side of the slide bearing, and because of a differential pressure applied above the slide bearing, the admittance of the material to be conveyed into the slide bearing is ensured and the shaft guided in the slide bearing is therefore sufficiently lubricated.
For fluid flowing at a higher viscosity, the admittance to the slide bearing and the distribution over the width of the bearing can be facilitated by a lubrication groove, as described, for example, in European Patent Document EP-0 620 368.
Fluids with an unknown elastic behavior often have the disadvantage that the fluid pressure in the lubrication groove is insufficient for pulling the lubricating fluid, that is, the material to be conveyed, into the gap between the slide bearing and the shaft.
It is therefore an object of the present invention to provide a slide bearing in the case of which a sufficient lubrication is ensured, particularly also with respect to a fluid flowing at a higher viscosity.
This object is achieved according to preferred embodiments of the invention by providing a slide bearing wherein the lubrication groove is constructed to be ending flatly in an area of an edge which acts as an inlet edge into a slot between the slide bearing and the shaft with respect to the shaft rotating direction.
The invention has the following advantages: Because of the flat construction of the entry edge by way of which lubricating medium, that is, conveyed medium, arrives directly in the slot between the slide bearing and the shaft, the conveyed medium has enough time for sufficiently reducing the expansion tensions which occur because of the cross-sectional changes and the meeting of the continuity equation and thus reducing the elasticity-caused additional pressure requirement. Generally and particularly in the case of cellulose-containing conveyed mediums, this is an important advantage.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.